AB1294 CO-OCCURRENCE OF IgG4 RELATED DISEASE AND OTHER SYSTEMIC IMMUNO-MEDIATED DISORDERS.
Authors: V. Batani, M. Lanzillotta, F. Chiabrando, G. Mancuso, J. Mahajne, L. I. Belli, L. Dagna, E. Della Torre
Journal: Annals of the Rheumatic Diseases (2022)

Background IgG4-related disease (IgG4RD) is a fibroinflammatory disease with unique clinical and pathophysiological features. According to the recently released Classification Criteria, the presence of other concomitant immunological disorders (OID) represents an exclusion criterion for the classification of IgG4RD (1). Rigorous application of the Classification Criteria, however, can lead to misdiagnosis because our increasing appraisal of IgG4RD indicates that this condition may coexists with OID (2). Objectives To describe IgG4RD presentation in the context of OID. Methods IgG4RD was diagnosed based on definitive histological findings. OID were diagnosed based on specific classification/diagnostic criteria. Results In six out of 234 (3%) patients IgG4RD occurred in accompaniment with OID, including two patients with sarcoidosis (33%), two with granulomatosis with polyangiitis (33%) one with eosinophilic granulomatosis with polyangiitis (16%) and one with Takayasu arteritis (16%). In three cases IgG4RD preceded OID (Table 1). Table 1. *ACR / EULAR 2017 provisional classification criteria for GPA **ACR 1990 Classification criteria for EGPA ***Modified diagnostic criteria for Takayasu arteritis. Shanna et al. 1995. Abbreviations: AZA: Azathioprine; CYC: Cyclophosphamide; EGPA: Eosinophilic Granulomatosis with Polyangiitis; ENG: electroneurography; GPA: Granulomatosis with Polyangiitis; IgG4RD: IgG4 Related Disease; INFX: Infliximab; F: female; M: male; MPDN: Methylprednisolone; MTX: Methotrexate; N: No; PDN: Prednisone; RTX: Rituximab; TCZ: Tocilizumab; Y: Yes GENDER (Age at IgG4RD diagnosis^ ) M (56) M (69) F (47) F (51) M (65) F (16) IgG4RD Organs involved pancreas, biliary tract, lymphnodes, nasal cavities, skin, ascending aorta salivary glands, pancreas, biliary tract, lung eyelid periorbital region, lacrimal gland meninges, abdominal aorta peritoneum ACR/EULAR score 34 36 20 21 24 26 Definite histological diagnosis Y Y Y Y Y Y (peritoneal lesion?) (pancreas, lymphnodes) (salivar glands, lung) (eyelid) (periorbiatl tissue, lacrimal gland) (meninges) Induction of remission therapy PDN + AZA PDN AZA PDN PDN + MTX PDN + MTX Response Y Y Y Y Y Y Relapse (years after treatment ) Y (6) Y (10) N Y (0,5) Y (5) N Second line therapy RTX RTX - MPDN + RTX PDN - OTHER IMMUNOLOGICAL DISEASE Diagnosis Sarcoidosis Sarcoidosis GPA GPA EGPA Takayasu Organs involved lymphnodes over and infra diaphragmatic, axillary, laterocervical, lumboaortic, inguinal, hepatic pulmonary and over and infradiafragmatic lymphnodes tracheal cartilage pulmonary nodules, scleritis respiratory tract (asthma), skin, peripheral nervous system, blood eosinophilia left subclavian artery, left common carotid, anonymous artery, thoracic aorta, suprarenal abdominal aorta, right pulmonary artery Classification criteria fulfilled? not available not available Y* Y* Y** Y*** Autoantibody none none c-ANCA c-ANCA p-ANCA none Definite histological diagnosis Y (lymphnode) Y (paratracheal lymphnodes) not available Y (pulmonary nodule) Y (skin biopsy) not available Timing of diagnosis vs IgG4RD subsequent previous previous contemporary previous contemporary Years after/before IgG4RD diagnosis 2 1 12 0 3 0 Treatment PDN PDN + MTX PDN + AZA PDN PDN + CYC INFX Response to treatment Y Y Y Y Y N Conclusion Our data demonstrate that IgG4RD can occur in overlap with OID, especially granulomatous diseases. Further research is needed to define whether this clinical scenario is associated with different pathological bases and long-term outcomes. References [1]Wallace ZS et al., Ann Rheum Dis, 2020 [2]Mizushima I et al., Rheumatology, 2021 Disclosure of Interests None declared